2012 Small World In Motion Competition

Sperm of two different males (green and red) competing within the female reproductive tract of the fruit fly Drosophila melanogaster. Competition between sperm is a widespread phenomenon throughout the animal kingdom and a powerful evolutionary force driving species diversity. However, it has been nearly impossible to study the fundamental biological processes associated with such sperm competition, occurring whenever sperm from different males mix inside of females. The very recent development of genetically modified fruit flies that produce sperm with either green- or red-fluorescent heads (as seen in the movie) is now allowing us to answer important biological questions.